Four of the 10 major deserts of the world are located in North America. One state, Arizona, has all four deserts within its borders. For decades scientists have traveled from around the world to this southwestern state to study its desert ecosystems. The proximity of the four deserts gives biologists, geologists, climatologists, ecologists and many other research specialists an opportunity to gather vast amounts of scientific information within a relatively concentrated area.
Deserts cover approximately one-third of Arizona. The terrain ranges from powdered earth and fine sand to rocky outcroppings interspersed with mountains sculpted by volcanic activity. Where the earth is soft with little vegetation, strong winds sometimes cause rolling dust storms that can cut visibility to almost zero. The majority of these storms occur in Pima and Maricopa County during the early summer months.
Some areas of the deserts of Arizona have giant saguaros, prickly pear cactus and mesquite trees and smaller plants sharing the land giving it a more lush appearance. There are also dangerous, roughly contoured areas that are criss-crossed by gullies prone to flash flooding during summer monsoons. Rivers, stands of pine, tundra and parched earth can all be found in Arizona’s deserts
Flash floods, severe lightening storms, poisonous and carnivorous animals, heat stroke and the possibility of dying of dehydration within miles of a large city can catch both the state’s visitors and residents unawares if proper preparation is ignored. Arizona media, state park rangers, and visitor’s centers continuously remind those going into a desert environment to take plenty of water and plan for significant drops in temperatures when the sun goes down.
While conditions can be harsh there is also a great beauty to be found in these ecosystems. Surreal plants, cacti and wildflowers with brilliant colors, high deserts with waving grasses and brilliant blue skies, elk, cougar, migrating hummingbirds; a diversity found only in Arizona’s deserts.
In the southeastern corner of Arizona, the Chihuahuan Desert covers over 200,000 square miles making it the largest desert in North America. Most of the desert’s land mass is found across the border in Mexico with areas extending into Arizona, Texas and New Mexico.
In the southwestern region, the Sonoron Desert covers around 120,000 square miles and lay mostly in Arizona. It is the hottest of the four deserts and surprisingly, attracts the most tourists. The pleasant winter temperatures bring people living in the snow-bound areas of the world. Winter visitors flock to Tucson, Phoenix and Scottsdale but hurry back to their homes, usually in early May, to avoid triple digit temperatures from June until October.
To the southeast, lays the Mojave Desert. At around 22,000 square miles, the Mojave Desert is one of the best protected ecological areas in the United States. It is in western Arizona and follows the Colorado River southward. Because winds between 40 and 50 miles an hour are continuous in the area, large wind generators are a common sight in this desert. The underground Mojave River flows through this desert.
Arizona’s northernmost desert area is called the Great Basin. It has 190,000 square miles with boundaries extending into California, Utah and Arizona. Being so far north, it has cooler temperatures and more rainfall. The four-corner area, the point where Colorado, Utah, New Mexico and Arizona meet, is located in the northeastern part of the Great Basin.
Arizona deserts can be identified by plants, animals and birds living within each ecosystem. Elevation, longitude and latitude are the defining factors.
To the south, the Chihuahuan desert has little rainfall but both the Pecos and Rio Grande Rivers run through the scorched area creating extensive riparian areas where native trees thrive. The water and vegetation in these areas attract many types of wildlife. With a difference of around 3500 feet in its elevation, the Chihuahuan Desert offers several different types of environments. Mesquite, Ocotillo and the Creosote bush is found here but the plant indicator for the Chihuahuan Desert is a type of Agave called lechugilla.
Moving northward, the land becomes more verdant. This is the Sonoran, the hottest of the four deserts. Phoenix and Tucson are located within its borders. Animals, including predators, are more evident as food and shelter becomes more obtainable. There are a number of both dry and wet riparian areas in the Sonoran Desert. Dry riparian are those arroyas that have water sporadically and infrequently. The plants usually found in wet riparian areas are also found in these dryer areas. The Verde River and Gila (pronounced “Hee-la“) Rives are two well-known Sonoran wet riparian habitats.
Moving into the Mojave Desert, situated between the Sonoran and Great Basin deserts, vegetation becomes more sparse due to an average annual rainfall of around 5 inches. Hearty heat-dwellers such as snakes, lizards, burrowing mammals, cougars and javelina live in this desert. The Colorado River cuts through the northeastern part of this desert. Hoover Dam connects Arizona and Nevada and is a favorite tourist attraction. The indicator plant here is a tree-like yucca cactus called a Joshua Tree.
The Great Basin desert, northern most of Arizona’s deserts, is where pinion pines, more rainfall and cooler temperatures make it an ideal place for many different species of plants and wildlife. With its elevation ranging from 3,000 feet up to 6,500 feet, species of lizards and horned toads are found in the lower elevations while golden eagles and even some longhorn sheep and elk are found in higher elevations. Sagebrush is the indicator plant for the Great Basin desert but stands of pine, juniper and aspen also live within this desert.
From the lowest elevation of 70 feet on the Colorado River in Yuma, AZ to Flagstaff’s Mt. Humphrey’s rising to almost 13,000 feet, Arizona deserts are truly eco and geological wonders.